The instant invention relates to a coffee machine as well as to a coffee machine mounting method.
It is known from the prior art to control coffee machines by means of touch-sensitive operating elements comprising touch sensors. In particular, conductive surfaces are used thereby, by means of which a touch can be detected as capacitive elements.
The coffee machine can be controlled by means of such operating elements via logic means, in particular in the form of microcontrollers or the like, in particular in that further elements, such as in particular water heating means, a grinder and/or a brewing unit are controlled. For example, the type of the desired beverage and/or the roasting degree can be selected by means of the operating elements. On the basis of the changes of the capacitive characteristics of the touch sensors, the logic means detect a touch and react to it in a predetermined manner. Such logic means are common in particular as so-called surface-mounted device (SMD) components.
For creative reasons, an uneven shape is often selected for the outer shape of coffee machines, in particular for the front panels. Due to the fact that the outer contour of the operating elements needs to be adapted to this shape, flexible conductor foils are used, for example PE foils, which are imprinted with silver, or transparent foils, which are coated with indium tin oxide (ITO), to which the operating elements are applied.
However, such conductor foils are not very well suited for an assembly with commercial SMD components, because SMD components are on principle only embodied and intended for an assembly on a flat printed circuit board.
Among others, this is one reason why the logic means and further SMD components, such as sensing resistors, are arranged on additional printed circuit boards, which are arranged in a rear or inner area, respectively, of the coffee machine.
The operating signal of the touch sensors is conducted to the further printed circuit boards via long signal lines, mostly via a plurality of plug-in connections. This creates a plurality of contact locations and interference capacities, which oppose an exact evaluation of the operating signals. The design and mounting effort is also increased due to these additional lines.
An operating panel arrangement for washing machines and laundry driers is known from DE 10 2006 013 937 A1, in the case of which electrodes for calculating an operating finger position and evaluating means are arranged on a continuously curved printed circuit board. A bending of the printed circuit board can lead to hairline cracks in signal-conducting means (conductor paths) here.
A touch-sensitive operating element is known from US 2006/0238513 A1, wherein touch-sensitive sensors are connected via cables to logic means, which are arranged on a printed circuit board, which is located at a distance therefrom.
A similar setup follows from a capacitive touch switch, which is shown in DE 10 2007 035 455 A1.
DE 10 2011 077 902 A1 shows an operating and display device for household appliances comprising sensor electrodes, which are arranged on a straight printed circuit board, wherein a curved operating surface is arranged upstream of the continuously straight printed circuit board.
DE 10 2010 032 951 A1 shows a continuously curved printed circuit board for a capacitive touch sensor, wherein the printed circuit board is connected to a separate printed circuit board comprising evaluating electronics via a flexible connection.
DE 10 2011 078 985 A1 teaches possibilities for touch recognition of three-dimensional objects.